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MAT02, 03 Elektor preamp schematic

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#21
jacco,

Sorry that I did not read your post careful enough. How do you compare the sound of the opamp vs. discrete preamps? both hi-end ofcourse, but the sound?

resolution,

Thanks for that schematic. Yes that was the simplest one I was after because I want to check this vs. the one with the servo.

peranders,

Thanks for the update on availability. I will contact AD in India to get the MAT03s; I already have about 8 Nos. of MAT02s.
 
#24
Samuel Jayaraj said:
How do you compare the sound of the opamp vs. discrete preamps?
Click to expand...

Just build the circuit, you will not be dissapointed.
In my opinion Elektor made a very elegant design, with an attractive pricetag.

550C/560C are still my fav. small signal transistors.
Great specs, their low price makes them tops for selecting/matching.I still have 100s of them.
Types with lower noise ratings are way more expensive.

I think elektor made a number of poor designs.
Their Hitachi Mosfet Crescendo was built by the thousands,not a great amp in my view, the design loved to swing the wrong way.
I built the discrete preamp that was designed at the time of the 1st edition Crescendo's, and it was total crap.
As the designs were meant for DIY purposes Elektor took the path to designing circuits that were DIY foolproof for quite some time, stuffed with Miller,Lead,Lag compensation.
Elektor later designed circuits that were too difficult for most of their readers, their IGBT power amplifier was not a succes , i gathered, Mark Alexander's IGBT design just moderately.

I built an elektor poweramp with entrance SSM22**'s, at the time i gathered that the SSM used the lower end MAT's, beside the low cost package. Maybe that has changed, MAT0*'s still cost at least twice as much though.

I built this design because i liked it.
For a line stage you can probably use the SSM's if they differ a little from the regular MAT's, otherwise the circuit is even cheaper to build.
The offset servo gives you next to none DC, i love the sight of Leds and they produce far less noise than regular diodes.
Besides being subjective i am not going to state which is best, this circuit outperforms the initial double OP27 integrated circuit from elektor and it costs less.
Comparing it with the OPA627 is not fair moneywise, the lowest i know of abroad is like $20 each, the shop here around the corner sells it for $47.
Personally i rave about the OPA627/637, on another thread i just posted on how i even used a bunch of them in my 8 channel car amps.
Unlike the OP27 the OPA627 has been specifically designed for audio applications.
The japanese industry has been designing state of the art audio transistors for a long time, i am paying at most 1/5 th for Sanken's 1216 (and Toshiba's 5200) now that they have become more common compared to 15/20 ago, the Sanken's i regard as brilliant audio power transistors.
In my view the chip industry still has not reached the end level in integrated audio circuits.
Nelson Pass lately stated that some prefer white, some red.
I like the Burr Brown sound, even if it is integrated.

I agree with you that elektor's discrete design is not just another electronic mag circuit, it sounded wonderfull hooked up on several class A power amps with full power bias in 8 ohms and ESL's.
 
#25
Re: MAT02 or SSM2210

Elso Kwak said:
Also I noticed different sound.
Click to expand...

Nice thread, Elso.
A lot of the details in your KISS layout underscribe my findings.
e.g. : as i have the skills and possibilities of constructing steel casings i see no point in alloy case building, mine are 1/3 " plate minimum with threaded holes for hardened/chromed hex bolts.

Is it possible to give some specific details on the toroid choke cores you mentioned ?

I am asking because i am building a large number of Pass amps for an active system, currently thinking of adding two Zen XA's, for which i want choke regulation.
In 2005 i want to have a go at Pass's monster, for that i just hauled two 5000VA toroids in my garage.

The Amazon lines sounded nice, but remind me a tadd of Gregory Peck in Paraguay. You have twins ?:clown:

Wacko.
 
#27
discrete preamp Elektor !!!!

Hi !!!

I Just build the circuit & tested this preamp, finding its quality Appreciation in this Thread.
I am having some problems, This preamp is giving out DC ?ve10.23 volts, I have checked no shorts, I have Used Bc 550/560c Instead of MAT 02/03, due to the non availability of original matched transistors.

Hope guys here will help me.

Thanks
Arasuk
😀
 
#28
PCB Layout

Hi Nexus,

Sorry about the delay getting back to you.

As it happens I do. I use Pads PCB. I can email the file to you as is, or compile it into a multi-page pdf. It is a double layer with top ground plane.

I've included a 3 page pdf for your perusal.
P1. Schematic
P2. Top
P3. Bottom

All PCB layouts are 2:1 un-mirrored

If you need all the PCB details in pdf or CAM photo then can you give me a few of days - it my wife's birthday the day after tomorrow and things are just a bit manic right now with that and work.

Let me know what you require.

Kind regards

res
 
#30
Jacco,
I've built many crescendo's on my own PCB's and they're the best. I also have the Rotel RC990/RB980 combination+NAD 162/272, but they are not as good as the Crescendo.
Go figure. I use a homemade passive with the Crescendo's and they are way better than the commercial units.
Its a matter of opinion. I use them with Driade's boxes.
 
#31
Pre amp prob!!!

Hi



(I Just build the circuit & tested this preamp, finding its quality Appreciation in this Thread.
I am having some problems, This preamp is giving out DC ?ve10.23 volts, I have checked no shorts, I have Used Bc 550/560c Instead of MAT 02/03, due to the non availability of original matched transistors.)

Hope guys here will help me.

Thanks
Arasuk
 
#32
Hi Arasu,
Double check the connections on the input transistors . B,C,E are connected right ? You obviously have a dc problem. Chances are that you either have some part wrongly connected or have some track error ( where did you get the pcb ). Sometimes errors look fine even if you look at it 10 times. So take a big break and then look at it again.
Cheers.
 
#35
Mat Preamp!!!

Hi Ashok & siva,

Thanks for the reply, I checked the pcb again no shorts or any mistakes , still O/P of - 10.6 volts ,

:bawling:
The I/p Diff trans are not matched but then I should be able to get may be 100 Mv or 300 mv not -ve 10.6V
:bawling: :bawling: :bawling:

I had the same prob as mr samuel had I have mat 02 & mat03 ( PMI )But MAT 03 are NPN misprinted .

Ashok : I got the PCB done by Elektor Book after hunting for long long time for the back issue.I got it with LEGEND and Solder mask so no shorts shall happen.

Let me know if anybody faced the same prob and rectified .

Thanks

Arasuk
 
#36
Try to force a DC voltage through a high value resistor eg:1Meg.
to one i/p direct ie to the base of i/p trans. Use a 100K preset and connect either end of preset to the supply rails and the wiper thru 1Meg said resister. And note any change in the output offset voltage..........If it changes..then u had to match the trans pairs...try it and let me know
 
#40
Re: PCB Layout

resolution said:
Hi Nexus,

Sorry about the delay getting back to you.

As it happens I do. I use Pads PCB. I can email the file to you as is, or compile it into a multi-page pdf. It is a double layer with top ground plane.

I've included a 3 page pdf for your perusal.
P1. Schematic
P2. Top
P3. Bottom

All PCB layouts are 2:1 un-mirrored

If you need all the PCB details in pdf or CAM photo then can you give me a few of days - it my wife's birthday the day after tomorrow and things are just a bit manic right now with that and work.

Let me know what you require.

Kind regards

res
Click to expand...


Hi,

can U send me PCB files to bobannesic@gmail.com or just use my email below.

Boban
 
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